Magnetically operable switch



Feb. 19, 1957 E. SCHRACK MAGNETICALLY OPERABLE SWITCH Filed June 10, 1953 2,782,282 MAGNETICALLY OPERABLE SWITCH Eduard Schrack, Vienna, Austria Application June 10, 1953, Serial No. 360,771

Claims priority, application Austria June 26, 1952 9 Claims. (Cl. 200-111) This invention relates to a magnetically operable switch, particularly of small size, which comprises a base plate, a movable armature having a contact bridge firmly connected thereto, a magnet core connected to said base plate and in magnetic relation with said armature, and a straight bolt connected to the base plate and extending through and guiding said armature along a straight line and carrying at its end opposite to the base plate a stop limiting the movement of said armature along said bolt.

Such types of magnetically operable switches are known and distinguished by simple assembly and small space requirements. In the known type the guide bolt is suitably arranged in the axis of symmetry of the magnet system and firmly connected to the magnet system or the armature. In most cases that bolt serves at the same time as a carrier for a return spring loading the armature. The construction in which the armature stop carried by the bolt is centrically arranged relative to the armature, however, involves diiiiculties in manufacture because on the one hand the armature should be slidable with play on the guide bolt to ensure its snug engagement on the magnet core in order to avoid humming in the case of energization by alternating current, whereas on the other hand such play must not be excessive in order to ensure the perfect guidance of the contact bridge.

It is an object of the invention to provide a construction of the type described in which the advantages of said centrically arranged armature stop are retained whereas humming, which is inevitable in the case of a rigid assembly, is avoided.

To this'end it is a feature of the invention to provide in a magnetically operable switch the combination of a base plate, a movable armature having a contact bridge rigidly connected thereto, a magnet core connected to said base plate and in magnetic relation to said armature, and a straight bolt extending through and guiding said armature along a straight line and connected at one end to said base plate with freedom of pivotal movement on at least one axis transverse to the axis of the bolt and carrying at the other end a stop limiting the movement of said armature along said bolt.

Preferably the bolt is connected to the base plate with freedom of pivotal movement on a pivot axis transverse to the bolt axis and on an axis transverse to the bolt axis and said pivot axis.

According to another feature of the invention the magnet core is also movably connected to the base plate, preferably by means of the member connecting the bolt carrying the armature stop to the base plate. In that arrangement the magnet core is pivotally movable relative to the base plate independently of that bolt and is preferably movable in a direction parallel to the bolt axis.

The construction according to the invention ensures with safety the hum-free contact of the armature on the core.

Further details of the invention will be apparent from the subsequent description of an illustrative embodiment represented in Figs. 1 and 2 of the drawing, in which all United States Patent 2,782,282 Patented Feb. 19, 1957 ice parts not essential for the invention have been omitted or indicated only.

Fig. 1 is a cross-sectional view of the switch taken along line I--I of Fig. 2 and shows the armature in attracted position on the core.

Fig. 2 is an appertaining top plan view.

The magnet core 2 and the guide bolt 3 are individually movably connected to a saddle stuck out from the base plate 1 at the middle thereof with the pin 4, which ex tends parallel to the base plate through a clearance bore formed in the bolt and through an oblong hole formed in the core 2 and elongated in the axial direction of bolt 3. In order to damp the impact of the armature 5 on the core upon energization of the magnet the core 2 is cushioned by a resilient member 16 of rubber, felt, or the like, which is interposed between the core and the base plate. Thus the bolt 3 is pivotally movable relative to the base plate on the axis of pin 4 extending transversely to the axis of bolt 3 and on an axis transverse to the axes of bolt 3 and pin 4, due to the clearance between the bore in bolt 3 and the pin 4 extending therethrough and having a diameter smaller than that of the bore. The core 2 is pivotally movable on pin 4 independently of bolt 3 and is movable in a direction parallel to the axis of bolt 3 due to the vertical play between hole 15 and pin 4.

Arranged in magnetic relation with the core 2 the armature 5 is movable on guide bolt 3 and rigidly connected to contact bridge 6. The latter carries contact arms 7, which establish the electric connection between fixed contacts 8 and 9 mounted on insulating bodies 10, which may consist, e. g., of ceramic material. The magnet coil 11 is mounted on the base plate independently of the magnet core.

The resilient armature stop on guide bolt 3 is formed by a spring plate 12 and a cushioning rubber member 13. Independently of these parts two diametrally op posite spring-loaded pins 14 tend to move the contact bridge with the armature along a straight line, whereas the armature 5 and the magnet core 2 owing to their connection are movable in such a manner as to contact each other snugly in any case when the magnet is energized.

I claim:

1. In a magnetically operable switch the combination comprising a base, a movable armature having contact bridging means rigidly connected thereto, magnet core means connected to the base and in magnetic relation to the armature, straight guide means of such size as to allow loose guiding of the armature in a linear path and at one end connected to the base for pivotal movement about at least an axis transverse of the guide means, and stop means carried by the opposite end of the guide means, said loose guiding of the armature permitting the armature to seat against the core means to prevent humming.

2. In a magnetically operable switch the combination comprising a base, a movable armature having contact bridging means rigidly connected thereto, magnetic core means connected to the base and magnetically related to the armature, straight bolt means loosely extending through the armature for guiding same along a linear path and connected to the base for movement about at least an axis transverse of the guide means, and stop means carried by the bolt means for stopping the armature, said loose guiding of the armature permitting the armature to seat against the core means to prevent humming.

3. The combination according to claim 2 and wherein the connection between the base and bolt means is provided by pin means.

4. In a magnetically operable switch the combination comprising a base, amovable armature having contact bridging means rigidly connected thereto, magnet core means connected to the base and magnetically related to the armature, a straight belt at one end connected to the base for pivotal movement about at least an axis transverse of the bolt and extending loosely and centrally through the armature for guiding same along a linear path, and a stop carried by the other end of the bolt and engageable by the armature, said loose guiding of the armature permitting the armature to seat against the core means to prevent humming.

S. The combination according to claim 4 and wherein the connection between the base and bolt is constituted by pin means.

6. The combination according to claim 4 and wherein the connections between the base and the bolt is a pin and the bolt has an aperture receiving the pin and providing play therefor.

7. In a magnetically operable switch the combination comprising a base, a movable armature having contact bridging means rigidly connected thereto, a straight bolt loosely extending through the armature for guiding same alonga linear path, amagnetic core in magnetic relation to .the armature, a member pivotally connecting one end of the bolt to the base for movement about at least an axis transverse of the bolt and loosely mounting the core on the base for pivotal movement about the member independent of the bolt, and a stop carried by the opposite end of the bolt and limiting movement of the armature on the bolt, said loose guiding of the armature and loose mounting of the core permitting the armature to seat against the core to prevent humming.

8. In a magnetically operable switch the combination comprising a base, a movable armature having contact bridging means rigidly connected thereto, a magnet core magnetically related to the armature, a straight bolt extending loosely through the armature for guiding same along a linear path, a member pivotally connecting one end of the bolt to the base for movement about at least an axis transverse of the bolt and loosely mounting the core for pivotal movement about the axis of the member independent of the bolt and for movement axially of the bolt, and a stop carried by the opposite end of the bolt and limiting the movement of the armature, said loose guiding of the armature and loose mounting of the core permitting the armature to seat against the core to prevent humming.

9. In a magnetically operable switch the combination comprising a base plate carrying a pin in parallel relation thereto, a movable armature having contact bridging means rigidly secured thereto, resilient cushioning means on the base plate, a magnet core supported on the cushioning means and magnetically related to the armature, a straight bolt loosely extending through the armature for guiding same along a linear path and having near one end a transverse hole Wider than the pins diameter, the core having a hole of a cross section elongated axially of the bolt, both holes receiving the pin, the bolt carrying at the opposite end a stop limiting the movement of the armature on the stop, said loose guiding of the armature and loose mounting of the core permitting the armature to seat against the core to prevent humming.

References Cited in the file of this patent UNITED STATES PATENTS 768,549 Stewart Aug. 23, 1904 803,486 Hill Oct. 31, 1905 1,238,667 Halbleib et al. Aug. 28, 1917 FOREIGN PATENTS 470,532 Great Britain Aug. 17, 1937 655,812 Germany Ian. 24, 1938 

